TSL26717FN Просмотр технического описания (PDF) - austriamicrosystems AG

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производитель

TSL26717FN

DIGITAL PROXIMITY DETECTOR

austriamicrosystems AG 

TSL2671

DIGITAL PROXIMITY DETECTOR

TAOS118 − JANUARY 2011

Functional Block Diagram

LDR

IR LED Constant

Current Sink

Interrupt

INT

Prox Control

Upper Limit

SCL

VDD

Prox

Prox Prox

Integration ADC Data

Lower Limit

SDA

Wait Control

lid GND

CH0

CH1

a Detailed Description

v The TSL2671 light-to-digital device provides on-chip photodiodes, integrating amplifiers, ADCs, accumulators,

clocks, buffers, comparators, a state machine, and an I2C interface. Each device combines a Channel 0

ill photodiode (CH0), which is responsive to both visible and infrared light, and a channel 1 photodiode (CH1),

which is responsive primarily to infrared light. Proximity detection can occur using either or both photodiodes.

Two integrating ADCs simultaneously convert the amplified photodiode currents into a digital value providing

t up to 16 bits of resolution. Upon completion of the conversion cycle, the conversion result is transferred to the

G s data registers.

Proximity detection requires only a single external IR LED. An internal LED driver can be configured to provide

A t a constant current sink of 12.5 mA, 25 mA, 50 mA, or 100 mA of current. No external current limiting resistor

is required. The number of proximity LED pulses can be programmed from 1 to 255 pulses. Each pulse has a

s n 16-μs period. This LED current, coupled with the programmable number of pulses, provides a 2000:1

contiguous dynamic range.

m te Communication to the device is accomplished through a fast (up to 400 kHz), two-wire I2C serial bus for easy

connection to a microcontroller or embedded controller. The digital output of the device is inherently more

a n immune to noise when compared to an analog interface.

The device provides a separate pin for level-style interrupts. When interrupts are enabled and a pre-set value

o is exceeded, the interrupt pin is asserted and remains asserted until cleared by the controlling firmware. The

interrupt feature simplifies and improves system efficiency by eliminating the need to poll a sensor for a proximity

c value. An interrupt is generated when the value of a proximity conversion exceeds either an upper or lower

l threshold. In addition, a programmable interrupt persistence feature allows the user to determine how many

Technica consecutive exceeded thresholds are necessary to trigger an interrupt.

Copyright E 2011, TAOS Inc.

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www.taosinc.com

The LUMENOLOGY r Company

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